1. Field of the Invention
The present invention relates to a technique for extracting and browsing an electronic mail created and transmitted by using the HTTP (HyperText Transport Protocol) passing through a data relay apparatus such as a proxy server or the like.
2. Description of the Related Arts
It becomes possible to extremely simply and effectively exchange various information, according to development of the network technique. For example, it is possible to attach a material to be used in a conference to an electronic mail and then deliver the relevant electronic mail to the attendees before the relevant conference is held, without spending time and effort.
However, although the information can be easily exchanged according to the development of the network technique, a risk that important confidential information easily leaks out increases.
In addition to such a premise, a company is required to properly deal with information according to the enforcement of a personal information protection law or the like. Consequently, for example, as a countermeasure for a leakage of information, a system of checking the contents (text information such as a destination, a body text and the like, the content of an attached file, etc.) of an electronic mail transmitted from the inside to the outside, and of inhibiting from transmitting the relevant electronic mail if the contents thereof coincide with a predetermined condition is introduced into many companies.
Further, the system like this is often a system which stores the transmission data to be transmitted to the outside so that an administrator can browse and check the contents thereof. Consequently, it is possible to reduce a risk that important confidential information leaks out from the inside of a company or a risk that information being adverse to a company flows out.
Furthermore, if some problem occurs, it is possible to check which data flowed to where in which route, by analyzing the stored transmission data.
On the other hand, the risk of information leakage or outflow of adverse information through a network depends not only on transmission of electronic mails but also on another reason. Namely, there is the same risk even in a Web service which uses the HTTP (HyperText Transport Protocol). For example, leakage of confidential information, outflow of adverse information or the like may also occur due to posting of messages to a BB (Bulletin Board) on the Internet. Since the Web services on the Internet which use the HTTP are diversified, companies are required to cope with leakage of information for each service.
As a representative example of the Web services, there is a service for transmitting and receiving an electronic mail by using the HTTP. In this service, it is possible to transmit and receive the electronic mail by using general-purpose browser software, namely, without using any electronic mail application. In the following, the electronic mail which is transmitted and received by using the HTTP is called a Web-based e-mail (for example, see Japanese Patent Application Laid-Open No. 2004-348202).
Since the protocol for mail transmission control and browsing of a Web-based e-mail like this is different from that of a conventional electronic mail (based on SMTP (Simple Mail Transfer Protocol)), it is impossible to use the relay control method and the browsing method for the conventional electronic mail. Further, by using the technique disclosed in Japanese Patent Application Laid-Open No. 2004-348202, it is possible to execute communication control and browsing by using a specific keyword. However, in such a case, unlike the conventional electronic mail communication control and browsing system, it is impossible to execute minute communication control based on the information such as a destination, a CC (carbon copy), a subject matter and the like, and it is also impossible for an administrator to browse the electronic mail.
Further, if it intends to execute the communication control and/or the browsing as described above, it is impossible to do so only by considering a difference of the protocol, because there is no unified protocol for the conventional electronic mail. Furthermore, since the Web-based e-mail is essentially different from the electronic mail in the point that the Web-based e-mail is constituted by plural HTTP transactions, there is a problem that an administrator has to correlate one information with another information when he/she intends to browse the Web-based e-mail.
In addition, the electronic mail is generally created by plural steps of storing a draft, adding an attached file, deleting the attached file, and the like. Thus, it is required to select, from several levels, the level that the administrator intends to browse. More specifically, it is required to select whether to browse only the finally transmitted electronic mail or to browse all the communication data including the data at the draft storing level, the data at the attached file adding and deleting level, and the data at the final transmitting (to a server) level. However, such a technique is not disclosed in Japanese Patent Application Laid-Open No. 2004-348202.
In a case where the conventional electronic mail is created, the process for handling the data of this mail until it is transmitted is closed in an electronic mail application on a client terminal apparatus. On the other hand, in a case where the Web-based e-mail is created, communication based on the HTTP starts in response to an electronic mail creation start operation.
For this reason, to enable the administrator to check to where which data was flowed in which route, it is important to acquire, as well as the electronic mail data, the information of a mail creation start method as auxiliary information. However, the conventional technique could not cope with such a situation.